Measurement of Neutron Parameters in the Treatment Beamof In-Hospital Neutron Irradiator

In order to verify the design specifications of in-hospital neutron irradiator (IHNI), the neutron fluence rates at the exit of its thermal and epithermal neutron beams were measured by using the method of cadmium difference. The radial distribution of the different components of the treatment beam exit was measured using a scanning device with a diamond detection unit. The results show that the thermal neutron fluence rates are 1.75×10⁹ cm^-2·s^-1 and 6.57×10⁷ cm^-2·s^-1 at the center of the thermal and epithermal neutron beams, respectively, and the epithermal neutron fluence rates are 1.41×10⁷ cm^-2·s^-1 and 3.14×10⁸ cm^-2·s^-1 at 30 kW full power operation; The vast majority of the treatment beam components are distributed within the beam aperture, with an exponential drop-off near the beam edges. The measurement results provide parameter support for subsequent related testing and experiments of In-Hospital Neutron Irradiators.